Luminescence of Bi4 Ge3 O12 : Spectral and decay properties

Abstract

Intense broadband emission in the visible is observed from crystals of Bi4Ge3O12 under optical and x-ray excitation. From measurements of absorption, reflection, fluorescence, and excitation spectra, the emission is assigned to 3P1 → 1S0 transitions of Bi3+. The Stokes shift is large, [inverted lazy s]14 000 cm−1. The temperature dependences of the fluorescence intensity and lifetime in the range 77–400 °K establish that nonradiative decay becomes significant at temperatures ⪞250°K. Comparison of the properties of Bi4Ge3O12 with those of Bi12GeO20 and other bismuth-activated materials demonstrates the importance of the Stokes shift and the 1S-3P energy difference in determining the luminescence behavior. The use of Bi4Ge3O12 as a laser host crystal for rare-earth and iron group activator ions, and as a scintillator material is discussed briefly.

Bi3+ luminescence in ABiO2Cl (A=Sr, Ba) and BaBiO2Br

“…1). Transitions between 1 S 0 and 3 P 0 , 3 P 1 , or 3 P 2 are spin forbidden, however, the 3 P 1 level undergoes mixing with 1 P 1 by spin-orbit coupling, allowing the 1 S 0 ↔ 3 P 1 transitions that are frequently observed in photoluminescence measurements [1,3,4,6,7,20]. The 1 S 0 → 1 P 1 transition is also observed in some materials.…”

“…The 1 S 0 → 1 P 1 transition is also observed in some materials. In the case of Bi 3+ , broad emission peaks, whose number and positions depend on the crystal field around the cation, and large Stokes shifts are commonly observed [1,3,4,7,20,21]. All three Sillen phases are isostructural, crystallizing in the orthorhombic space group Cmcm [13].…”

“…Trivalent bismuth cations in inorganic compounds or hosts commonly exhibit interesting luminescence properties originating from the excitation and relaxation of its 6s 2 inert lone pair electrons [1][2][3][4][5][6][7]. In this regard, an investigation of compounds containing Bi 3+ has great potential towards the discovery of new intrinsically luminescent materials.…”

“…This work introduces photo-and radio-luminescence properties of these three members of the Sillen bismuth oxyhalide family. Their luminescence properties are compared to Bi 4 Ge 3 O 12 (BGO), an important material with electrooptic [16,17] , nonlinear optic [18] , and scintillation [2,7] capabilities. The preparation, photoluminescence, and time resolved x-ray luminescence of these compounds are detailed in this report.…”

Instrumentation for Time-of-Flight Positron Emission Tomography

“…In addition, limited sensitivity (stopping power), low light output and the need for costly electronics restricted the first-generation ToF-PET to only research and consequently led to the demise of ToF-PET research at that time. During the 1970s and early 1980s, bismuth germanate (BGO) was used as the standard scintillator for PET detectors because of its high detection efficiency and acceptable light output in commercial PET systems [39]. However, the detector based on this scintillator is not suitable for ToF-PET because of its low light output and relatively long decay time.…”